The 150-Member Markush Genus With Two Data Points
NovaCure Pharmaceuticals filed a nonprovisional application in 2023 claiming priority to a 2022 provisional. Claim 1 recites a genus of kinase inhibitors: 'wherein R1 is selected from the group consisting of 150 optionally substituted aryl and heteroaryl groups.' The specification discloses a common bicyclic core, synthesizes four species, and reports IC50 data for only two. The examiner issued a non-final rejection under 35 U.S.C. 112(a) for lack of written description and enablement, asserting that the genus is not adequately described because the disclosure does not demonstrate possession of the full scope. The examiner also rejected claim 1 under 112(b) because 'substantially pure' is used without a defined threshold. The client wants to keep the broadest possible claim and asks whether the data for two species can support the genus. The specification defines purity only in Example 3 as 'at least 98% by HPLC area percent.' The 2022 provisional contains the same four species and the same two data points; it does not contain the common core generalization.
1. Assess the examiner's written description and enablement rejections. What facts in the disclosure help or hurt, and what legal standard applies?
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The written-description rejection is likely supported, but the examiner must do more than assert breadth. Under § 112(a) and Ariad, the specification must demonstrate possession of the full claimed genus. Courts look at the genus's structure, the number of species, the nature of the substituents, and the amount of representative data. A 150-member Markush group with four synthesized species and two IC50 values is a large genus in an unpredictable art. The common bicyclic core helps, but if the 150 aryl and heteroaryl groups vary widely in size, electronics, and metabolic stability, the disclosure may not show that the inventor possessed the full scope. The two data points may describe the four species but not the remaining 146.
Enablement is a separate question under the Wands factors: breadth, direction, examples, and predictability. Two data points and four examples may not enable the full genus without undue experimentation. However, the examiner cannot rely on a bare conclusion; the rejection should identify why the genus is not representative. The § 112(b) rejection of substantially pure is stronger: the term is relative and the claim does not specify the threshold, although the specification's Example 3 defines at least 98% by HPLC. The claim should be amended to recite that definition if the specification supports it.
2. Draft a responsive strategy: propose a claim amendment, the supporting remarks, and any declaration evidence. Identify what you must not do.
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Amend claim 1 to a subgenus of 12 species that share a defined substituent pattern, include the four synthesized species, and add dependent claims to the two species with data. In the remarks, do not concede that the full genus is undescribed; instead argue that the amended subgenus is a representative number of species with a common structural core, and that the specification provides a rational selection rule. Cite the specification's common core and the synthetic routes for the four species.
For enablement, submit a § 1.132 declaration from an expert stating that the 12 species can be made using the disclosed routes and that the two data points are representative across the subgenus. Do not submit new post-filing data to cure the written-description defect; post-filing data can support enablement but cannot create possession. Do not argue that the 2022 provisional supports the full genus if the provisional contains the same limited data and no generalization. If the examiner maintains the rejection, narrow further to the four species or file a continuation with a claim set limited to the two species with data. Amend substantially pure to at least 98% pure by HPLC area percent only if that definition is in the specification; otherwise define purity by the method already disclosed.
3. Explain how the amendment affects priority and whether a continuation or continuation-in-part is needed.
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The amendment to a 12-member subgenus is supported by the 2023 nonprovisional if the 12 species are within the disclosed 150 and the common core is described. Priority to the 2022 provisional is doubtful for the subgenus because the provisional contains only the four species and two data points, not the common-core generalization or the 12-member selection. The safe assumption is that the amended claims receive the 2023 filing date. That is acceptable if no intervening art between 2022 and 2023 is material.
A continuation-in-part is unnecessary unless the client wants to add new species, new data, or a new selection rule not in the 2023 application; a CIP would give those claims a later effective date and could expose them to intervening art. A continuation is also unnecessary while the application is pending; amend in place. If the examiner rejects the subgenus and the client wants to preserve the broader genus for appeal, file a continuation before allowance with the broader claim set and keep the narrower claims in the parent. Do not add new matter to the 2023 application; new species or data must go into a CIP.